Question

Which of the following conditions is not necessary for a change in the direction of propagation when a light Ray goes from one medium to another ?

⬜ The light Ray must be incident at an angle greater than 0° with respect to the normal at its point of incidence.
⬜The two media must both be transparent.
⬜The two media must have different refractive indices.
⬜The incident light rays must always have only the blue colour.​

Answer 1

Answer:

For refraction to occur substances must be transparent and light ray must pass from region of one index of refraction to another i.e. both substances should have different refractive indices should and the light ray must impinge at an angle other than normal which must not be less than the critical angle.

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Answer 2

Answer:

If the incident ray follows the normal drawn perpendicularly on the junction plane of 2 mediums, it will not refract. Angle of refraction (angle between the refracted ray and the normal), 'r' also becomes 0 thus no change in direction occurs.

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